Nuclear power is the cleanest and only large-scale energy-producing technology that does not emit air pollutants like soot, ash or Sulphur dioxide which increases greenhouses gases. In addition, it isolates its waste from the environment and requires a relatively small amount of land. They can be built in urban or rural areas, and do not radically alter the environment around them.

However, the byproduct of nuclear energy is radioactive material. Radioactive material is a collection of unstable atomic nuclei. These nuclei lose their energy and can affect many materials around them, including organisms and the environment. Radioactive material or Nuclear waste can be extremely toxic, causing burns and increasing the risk for cancers, blood diseases, and bone decay.

Nuclear waste is what is left over from the operation of a nuclear reactor. Nuclear waste is mostly protective clothing worn by workers, tools, and cloths that have been in contact with radioactive dust. Radioactive waste is long-lasting. Materials like clothes and tools can stay radioactive for thousands of years. Nuclear waste is properly regulated by the government while disposing it off in order to mitigate its impact on the environment around it. 

Nuclear waste comes from a number of sources. Most of the waste originates from the nuclear fuel cycle and nuclear weapons reprocessing. Other sources include medical and industrial wastes, as well as naturally occurring radioactive materials (NORM) that can be concentrated as a result of the processing or consumption of coal, oil and gas.

All parts of the nuclear fuel cycle produce some radioactive waste

Unlike other industrial wastes, the level of hazard of all nuclear waste – its radioactivity – diminishes with time. Eventually all radioactive wastes decay into non-radioactive elements. The more radioactive an isotope is, the faster it decays.

The main objectives in managing and disposing of radioactive (or other) waste are to protect people and the environment. This means isolating or diluting the waste so that the rate or concentration of any radionuclides returned to the biosphere is harmless. To achieve this, practically all wastes are contained and managed, with some clearly needing deep and permanent burial. From nuclear power generation, unlike all other forms of thermal electricity generation, all waste is regulated – none is allowed to cause harmful pollution.

Types of Nuclear waste

Nuclear wastes are normally classified as low, medium or high-level, according to the amount and types of radioactivity they contain. The high-level waste produced by nuclear reactors is the longest lasting contamination risk of a nuclear power plant.

Exempt waste & very low-level waste

Exempt waste and very low-level waste (VLLW) contains radioactive materials at a level which is not considered harmful to people or the surrounding environment. It consists mainly of demolished material (such as concrete, plaster, bricks, metal, valves, piping, etc.) produced during rehabilitation or dismantling operations on nuclear industrial sites. Other industries, such as food processing, chemical, steel, etc. also produce VLLW as a result of the concentration of natural radioactivity present in certain minerals used in their manufacturing processes.

Low-level waste

Low- and intermediate-level waste are the tools, protective clothing, wiping cloths, and other disposable items that become contaminated with small amounts of radioactive dust or particles at nuclear fuel processing facilities and nuclear power plants. It does not require shielding during handling and transport and is suitable for shallow land burial. To reduce its volume, it is often compacted or incinerated before disposal. It comprises some 90% of the volume but only 1% of the radioactivity of all radioactive waste.

Intermediate-level waste

Intermediate-level waste (ILW) contains higher amounts of radioactivity and some requires shielding. It typically comprises resins, chemical sludges and metal fuel cladding, as well as contaminated materials from reactor decommissioning. Smaller items and any non-solids may be solidified in concrete or bitumen for disposal. It makes up some 7% of the volume and has 4% of the radioactivity of all radwaste. By definition, its radioactive decay generates heat of less than about 2 kW/m³ so does not require heating to be taken into account in design of storage or disposal facilities.

High-level waste

"Burning" of uranium fuel in a nuclear reactor leads to the production of "ash" or High-level Waste (HLW) which is highly radioactive and hot due to decay heat. It requires cooling and shielding. HLW accounts for over 95% of the total radioactivity produced in the process of electricity generation. HLW comprises highly-radioactive fission products and some transuranic elements with long-lived radioactivity. These are separated from the used fuel, enabling the uranium and plutonium to be recycled. Liquid HLW from reprocessing must be solidified. It is vitrified into borosilicate (Pyrex) glass, sealed into heavy stainless steel cylinders about 1.3 metres high, and stored for eventual disposal deep underground. This material has no conceivable future use and is unequivocally waste.

If used reactor fuel is not reprocessed, it will still contain all the highly radioactive isotopes. Spent fuel that is not reprocessed is treated as HLW for direct disposal. It too generates a lot of heat and requires cooling. However, since it largely consists of uranium (with a little plutonium), it represents a potentially valuable resource, and there is an increasing reluctance to dispose of it irretrievably.

There are two distinct kinds of HLW:

• Used fuel itself.
• Separated waste from reprocessing the used fuel.

HLW is a major focus of attention regarding nuclear power, and is managed accordingly.

Handling of high-level waste

Nuclear waste like uranium mill tailings, used reactor fuel can remain radioactive and dangerous to human health for thousands of years. Nuclear wastes are subject to special regulations that govern their handling, transportation, storage in a way that is environment friendly and non-hazardous to both workers and the general public.

Storage of used fuel that gives rise to HLW is mostly in ponds associated with individual reactors, or in a common pool at multi-reactor sites, or occasionally at a central site.

The radioactivity of nuclear waste decreases over time through a process called radioactive decay. Radioactive waste is often stored temporarily before disposal to reduce potential radiation doses to workers who handle and transport the waste. This storage system also reduces the radiation levels at disposal sites.

By volume, most of the waste related to the nuclear power industry has a relatively low level of radioactivity. Uranium mill tailings contain the radioactive element radium, which decays to produce radon, a radioactive gas. Most uranium mill tailings are placed near the processing facility or mill where they come from. Uranium mill tailings are covered with a sealing barrier of material like clay to prevent radon from escaping into the atmosphere, and then the barrier is covered by a layer of soil, rocks, or other materials to prevent erosion of the sealing barrier.

After storage for about 40 years the used fuel assemblies are ready for encapsulation or loading into casks ready for indefinite storage or permanent disposal underground.

Advantages of Nuclear Energy

Uranium costs are low relative to coal and natural gas.The operating cost of a nuclear power plant is low, and will continue to be reduced as plants become more efficient and operate for longer periods of time. New plant designs are safer and more efficient than those of older plants.

As the demand for electricity grows in the coming years, it will be necessary to build more nuclear power plants

The amount of radioactive wastes is very small relative to wastes produced by fossil fuel electricity generation.

Used nuclear fuel may be treated as a resource or simply as a waste.

Nuclear wastes are neither particularly hazardous nor hard to manage relative to other toxic industrial wastes.

Challenges of Nuclear Energy

Overall costs of construction and spent fuel storage are high and highly political. It takes longer to build a nuclear power plant than a coal or natural gas plant.

Radiation released from nuclear reactions must be contained, and radioactive spent fuel and nuclear waste must be safely and securely stored. Safety of nuclear power plants is always a major concern for the common public and the environment. Transporting nuclear waste across the country have challenges both regulatory and political.

 Used fuel and rods of nuclear poison are extremely radioactive. An uncontrolled nuclear reaction in a nuclear reactor can result in widespread contamination of air and water. This was what happened in Chernobyl, Ukraine, in 1986. Storage facilities for radioactive waste leaked, leading to huge steam explosion at one of the power plants. Radioactive material contaminate the soil and groundwater near the facility. This led to serious health problems for the people and organisms in the area. The environmental impact of the disaster was immediate. Cattle and horses in the area died.

While environmental impact studies have been conducted to make predictions, it is unknown exactly how long-term storage of Nuclear high-level waste, including nuclear spent fuel, will impact the environment.

www.nei.org, national geographic, www.world-nuclear.org, www.eia.gov

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